Manufacturing disk drives is a very competitive business. People that buy disk drives are demanding more and more for their money. For example, they want disk drives that are more reliable and have more capabilities. One way to provide more capabilities is to make the various disk drive parts smaller.
Contaminants in disk drives can cause damage to the disk drives. The possibility of contaminants causing damage increases as the disk drive parts are made smaller and smaller. Further, the reliability of disk drives can be improved by increasing the cleanliness of the process used for manufacturing the disk drive parts regardless of the disk drive part's size. Therefore, it is important to evaluate the cleanliness of the manufacturing process so that corrective measures can be taken if the cleanliness deteriorates but also as a way of evaluating whether changes to improving the cleanliness of the manufacturing process are working.